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Hello,I am setting up a Steinway action with all new parts.The string height is fairly consistent except the top treble section where it drops down about 3mm from around note 65.When putting the action on the keyframe,I noticed someone has removed about 5mm from just the treble end,so there is a gap between the action foot and keyframe,meaning it has to be pulled down with the screws.Presumably to compensate for the string height difference..The rest of the action sits nice and flat.Is it best to put a packer in the gap to keep the action level?-and have it undercentre?Wouldn't pulling just that one section down put a lot of stress on the keyframe and action?Not sure whats best to do with it!Anyone got any ideas??

Thanks for the replies Pianolive, that makes me feel better about the bend!-I'm not sure if it's an original steinway procedure or something thats been done later on at some point.Ok i just sent an email to Kent. Good idea. i hadn't thought about that!-Hopefully he can help with it.

I rebuild Steinway action frames as a sub-specialty, so I've seen many frames both vintage and more recent, after they have become tired.

It is very very seldom that a frame comes in with feet in a dead flat plane, even if the rails are not split and the solder is still good. Why? my guess is that even if a frame is soldered together dead flat at its first manufacture, the process of setting the beveled cleats, and the fact that the feet do not have a ground flat contact surface, mean that each foot, in a random fashion exerts a point load on the cleats and compresses the various cleats in a random fashion.

This point load compresses the cleat at contact unpredictably, and its reasonable that the feet are likewise randomly distorted to accomodate this condition.

As well, one or more cleat might not have been the same thickness as the others at manufacture,or, the cleat was not placed exactly the same as the other cleats. Since the cleats are usually wedges, uneven cleat insertion would mean the cleats were effectively different heights. Given that the cleats are wedges, the placing of cleats is very easy to screw up, even if you know what you are doing. Its time consuming to get it right.

Uneven cleats will force the frame into a contorted shape, especially if a cleat at the middle is shy of the rest. As the middle shy cleat is be pulled down, the end of the frame will lever up over the other cleats, creating a significant lift.

Add to that that sometimes its necessary to bend the feet of a soldered frame to correct a clearance issue with the key sticks. To do this, the feet are usually bent with a pipe wrench, or other fine surgical tool. This will definitely throw the affected foot out of plane.

When rebuilding a frame, unless I'm working with a rebuilder with serious action design chops, I return the feet to a passive fit to the existing cleats. That means I keep the out-of-planeness purposely. If I were to flatten it out, when the frame goes back on the keyframe, the whole keyframe would most likely have to be completely re-bedded.

As far as "did they do this on purpose"...no way. No manufacturer would distort the foot plane purposely. These frames, at the factory, are generic frames. They are not built custom to each piano...they'd go nuts and broke if they messed around like that.

You could prove how it was before you took it apart by putting the keys on the frame, screwing down the entire stack, and then testing to see how the bedding is. If the bedding is okay, chances are it was socked down before you took it apart. If it beds better with a shim, you're golden.

Forcing the feet down puts quite a bit of strain on the whole system, not my favorite, but if you change the way the feet set originally, whatever that was, you will most likely have to correct the bedding.

Greetings, If you want the keyframe to provide a stable base for the action you will have to keep the action rails from stressing the keyframe. Either shim the feet so that the action brackets all rest evenly on the keyframe, or bend the rails down. I prefer to shim the feet. If you don't do this, the springiness created in the keyframe will make its bedding weather dependent and it change with the seasons. Regards,

You want a stable platform for the action. Introducing a decided 'twist' to the assembly by stressing the top action onto the keyframe is not good. It won't be stable. The regulation will wander and the bedding will be problematic.

Shim/wedge the action to fit cleanly onto the frame. The screws are to secure it...not force it into place.

Thanks everyone, thats great.Very useful information Jim, i appreciate that.I will check the existing bedding to see if that gives some clues to the puzzle!I had remembered something about the keyframe bedding being unstable if the feet don't sit flat, which raised my initial concern.

James Carney
Full Member
Registered: 07/30/10
Posts: 440
Loc: new york city

Originally Posted By: Ed Foote

Greetings, If you want the keyframe to provide a stable base for the action you will have to keep the action rails from stressing the keyframe. Either shim the feet so that the action brackets all rest evenly on the keyframe, or bend the rails down. I prefer to shim the feet. If you don't do this, the springiness created in the keyframe will make its bedding weather dependent and it change with the seasons. Regards,

Ed, do you always remove the keys before fitting and shimming the stack to the keyframe?

Generally the Key bed to Hammer flange center pin is 5.75" and the repetition center flange pin is 3.25"

Steinway has been very consistent with this.

I would be curious to know where those key bed to center pin measurements fall on your piano.

add to that... what is the consistency of those dimensions across the frame when screwed down with the shim and then screwed down without the shim...measured at 5 of six locations across the frame, not just at one point.

I have seen once a top right front foot lowered, but just 1 or 2 mm, It may have been necessary for tone reasons, using a standard bored hammer with similar bore in high treble than in the mediums as it is the case actually .

I have met a few rare Steinway (originally ?) fitted with shorter heads in the high treble, but most often only the rake angle is adjusted to compensate for the lower string's plane.

Up to 3 mm the lowering of the strings plane in the high treble is not considered a problem , and the height taken in account for the action is in the 5 th octave or in the mediums, allowing for a light 2-3 mm overblow.

usually the height of the hammer center is consistent at 1 mm difference between left and right (center is of not interest as it will be different in the piano than on a table)

I would suppose an improper keyframe bedding creates that apparent difference, 5 mm is way too much in my opinion.

If not, it was an attempt to have a better touch or tone.

Indeed when mounting a new stack the feet are bend

Possibly a stack can be mounted because the center glide bolts are too much lowered, and will take that shape with time, I have met some that where touching on the sides but not on the center.

With the new digital protractors, you can easily see how strong is the string's plane in the high treble, and measure 3°

If the heads are long enough for the mediums, they will be underceetering there, and the energy of the hammer will be delivered only on the front of the head, not the best way to have a full tone.

I agree that any excess stress left in the bedding will lend to variations with seasons, but Steinways are designed originally to accept some (it even lighten the action and allows for an easy pearled tone, but doing so on an action which is not intended for will lend to instability)

Usually I find older Steinway actions with the extreme glide bolts protuberant twice more (and the old hardened oak key frame does not accept much stress) I put that on the desire of the tech to keep some stress within the action, so the extreme bolts are turned a hair from time to time (?) .

I have read that the NY keybed is not similar to the Hamburg, that the stress between the keyframe and keybed is not managed the same, but I have not recent pianos to verify (the older ones seem to have a front lip the same thickness everywhere, is it the case ?).

Edited by Kamin (11/10/1212:44 PM)

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Generally the Key bed to Hammer flange center pin is 5.75" and the repetition center flange pin is 3.25"

Steinway has been very consistent with this.

I would be curious to know where those key bed to center pin measurements fall on your piano.

add to that... what is the consistency of those dimensions across the frame when screwed down with the shim and then screwed down without the shim...measured at 5 of six locations across the frame, not just at one point.

Jim Ialeggio

Usually, with a keyframe laying on a table, the cleats line perfectly (are the same size).

But I know that position modifications are possible, the advantage of a flexible stack.

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Forcing the feet down puts quite a bit of strain on the whole system, not my favorite, but if you change the way the feet set originally, whatever that was, you will most likely have to correct the bedding.

Jim Ialeggio

Jim, to me the bedding is something I tweak depending of the seasons, more on some pianos than others, the wear also may oblige to bed again (the glide bolts can wear with friction)Bedding the Steinways is one of the most delicate task in grand regulation, I really worked that a lot, that helped me much on other grands, I really refined method and tips, after being able to notice an uneven bedding just with the tone or touch/feel (I have even heard improper keyframe bedding on recordings or detected that on a video !), As we aim for long term stability, once the first years of the instruments are passed (during those years there may be some key bedding tweaks) I noticed that S&S bedding is really more stable than on many instruments.

Eventually, the inner stress of the action will vary, key dip may change a hair with seasons, but the bedding once stabilized seem to stay solid, needing only really light tweaks every few years.

I have become lately a fan of the old times bedding method, with paper strip^s under the balance rail or glide bolts, without the keys, as a really secure method to find the more neutral bedding.

Tweaks tend to react and change the second day, and as the very even repartition of the action weight on the balance rail always provide an audible clear amelioration in tone, evenness and no "hard spots" I have been happy to see that this old times method is efficient. (one can take the opportunity to clean and lube the pins and mortise at that occasion.)

Different key frames ask for different strategy, so the paper strips method is well adapted to hardwood frames, but it can help even on a Yamaha or a Kawai.

Something I noticed, is that the back of the frame is often warped high due to the weak point where the UC pedal mechanism may pass.

I belive thatr the return spring is pushing there, soI am very attentive to have the UC pedal really tight.The force of the spring apply half on the leather of the UC movement, half on the left of the cavity, then I cross fingers and hope that this will avoid a warping high of the frame during humid season, and if it happens, that at last the return spring will not have the opportunity to push the frame even higher, as I suspect it can be the case if the UC movement mechanism is not retaining the force of the spring at some point... And I have met old hard wood frames without glide bolts really warped up a lot)

The parallelism between the strong return spring and the side of the action is also checked.

As a principle I never allow any play on the left pedal because of those side effects, supposed or real,

Some brands say you may be able to pull a paper strip from between the action and the cavity as soon the pedal is pushed, others even say that the paper strip can be pulled out with some rubbing with the pedal at rest, I use that last setup.

Edited by Kamin (11/10/1201:30 PM)

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It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills

If you want the keyframe to provide a stable base for the action you will have to keep the action rails from stressing the keyframe. Either shim the feet so that the action brackets all rest evenly on the keyframe, or bend the rails down. I prefer to shim the feet. If you don't do this, the springiness created in the keyframe will make its bedding weather dependent and it change with the seasons. Regards,

Ed, do you always remove the keys before fitting and shimming the stack to the keyframe? [/quote]

I remove the top action and keys, raise all glide buttons, bed the back and front rails, lower the glides until they just barely tap (slightly more so in the bass and none at the very top), and then place the top action on the frame. Any of the feet that don't touch the keyframe get shimmed at this position. With the weight of the keys back on them, the balance rail will drop the few thousandths onto the glides and the front and back rails will be pressed down by the spring while the action is stress-free on the frame.

After that, it is important to install the cheek blocks, press the una corda and recheck all the balance rail contact, and THEN, firmly press both damper pedal and una corda and check again. I do this because it is not uncommon for the use of both pedals together to flex the keybed enough to create a knock under one or more of the glides. If so, I turn the glides down until they don't knock, let go of the pedals, and check again.

I think this to be the most solid and durable approach, and has, in my experience, yielded the best results .

If you want the keyframe to provide a stable base for the action you will have to keep the action rails from stressing the keyframe. Either shim the feet so that the action brackets all rest evenly on the keyframe, or bend the rails down. I prefer to shim the feet. If you don't do this, the springiness created in the keyframe will make its bedding weather dependent and it change with the seasons. Regards,

Ed, do you always remove the keys before fitting and shimming the stack to the keyframe?

I remove the top action and keys, raise all glide buttons, bed the back and front rails, lower the glides until they just barely tap (slightly more so in the bass and none at the very top), and then place the top action on the frame. Any of the feet that don't touch the keyframe get shimmed at this position. With the weight of the keys back on them, the balance rail will drop the few thousandths onto the glides and the front and back rails will be pressed down by the spring while the action is stress-free on the frame.

After that, it is important to install the cheek blocks, press the una corda and recheck all the balance rail contact, and THEN, firmly press both damper pedal and una corda and check again. I do this because it is not uncommon for the use of both pedals together to flex the keybed enough to create a knock under one or more of the glides. If so, I turn the glides down until they don't knock, let go of the pedals, and check again.

I think this to be the most solid and durable approach, and has, in my experience, yielded the best results .

Regards, [/quote]

Very good procedure, nicely described, but don't you screw the action stack before final adjustments (and without the keys) ?

This sound like a good "defensive" approach. anyway.

Then you don't install any "stress" within the action, from there ? (on NY Steinways) ?

Edited by Kamin (11/10/1204:19 PM)

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It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills

>>Very good procedure, nicely described, but don't you screw the action stack before final adjustments (and without the keys)>

Hmmm.

Actually, there is no reason for the screws to be involved when my intention is to have all the feet in contact with the cleats and no stress in either the keyframe or the action rails. What I am looking for is two assemblies mated with each other without either one putting stress on the other. ( I suppose the same could be said of a marriage). Regards,

>>Very good procedure, nicely described, but don't you screw the action stack before final adjustments (and without the keys)>

Hmmm.

Actually, there is no reason for the screws to be involved when my intention is to have all the feet in contact with the cleats and no stress in either the keyframe or the action rails. What I am looking for is two assemblies mated with each other without either one putting stress on the other. ( I suppose the same could be said of a marriage). Regards,

Yes I understand that very well, but now on the Steinways we work on, the keyframe is stressed simply when the blocks are tightened. The stress is light and apply mostly on the front lip, but with a reaction from the balance and back of the stack, it sort of "lighten" the action and can change the tone/touch quite a bit.

On older ones the stress is often gone, and the keyframe apply flat.

I was instructed to tighten the action before bedding the balance rail, and that seem tho be the best way to have it clean and stress free, on other pianos than Steinways.

I believe that the screwed stack imply some invisible stress, something that cannot be detected with shims, so it is better to have it screwed (and more when the front screw are inclined).

But I agree with your checking it also may show if something warped and where.

Edited by Kamin (11/12/1204:26 AM)

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It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills

I was instructed to tighten the action before bedding the balance rail, and that seem tho be the best way to have it clean and stress free, on other pianos than Steinways.

I believe that the screwed stack imply some invisible stress, something that cannot be detected with shims, so it is better to have it screwed (and more when the front screw are inclined).

I would agree here. This is what I was referring to in my earlier post regarding random foot point loads. The unevenness of the bracket feet introduce concentrated and random point loads when screwed down. I have quantified this effect...actually I quantify it on every frame that comes in to my shop for rebuilding.

As I mentioned above, I shoot to reproduce the existing passive foot plane(uneven) when rebuilding a frame unless directed to do otherwise.

The first thing I do when setting up the frame for rebuild, is to mount bare pin flanges at 6 points along the frame (shank&whip). With the frame setting stress free and unscrewed on the jig, I take height readings off all the flanges individually. Then I look for any feet that are making passive secure contact with the mounting surface on the jig (poplar). I do this by tapping the feet. You can feel and hear when a foot is sitting passively secure on the jig base...there might be 4 or so passively secure feet.

If I were to screw those (say 4) secure, passive contact feet down, the flange heights all over the entire frame would change...sometimes by 2mm or so...depending where the initial 4 secure feet were along the frame. At first this didn't make sense to me, until I realized only one point of each of the secure feet, not the entire surface of the foot, but only one point was making passive contact. Screw that one point down, and it crushes the wood at the point load, until the entire foot makes contact. The compression at that point load may be .25-.75mm, but it then creates random levering effects over other parts of the frame, and accentuates the flange height changes, sometimes significantly. This point load compression scenario will be repeated on all 12 feet locations (2 per bracket).

The point load deformation creates an example of the classic "action interactiveness" effect, where one change effects all the other parts, and must be accounted for...or at least that how I approach it...

When the finished frame is installed on the keyframe, this "foot point load scenario" will be repeated, introducing stresses to the keyframe and action frame. From the in-situ bedding procedures perspective we are discussing here, this would suggest to me the the inevitable stress created by screwing down the frame should be expected and accounted for in the bedding order of events.

HI Jim ! I did not notice so high uneveness on the stacks I soldered, (also because the rails are cracked in that case generally, I cannot account the stack for an "original "geometry)

Your experimentation is interesting, for sure there is some amount of pressure between the foot and the wedge, and it may move the centers (I did not make such experiments, but I will)

I sold the stack on a flat bench, but I measure /verify the centers. As I use a "copy" jig I have find some nice uneveness in rails, as a warping in the mediums, that was only due to the soldering in my opinion.

Witch order for the soldering, would be the most secure, in your opinion ? (to avoid the warpage due to the soldering heat ?

I am unsure if it is better to begin in the center, or at the extremes. (my gig allows 3 points secured)

Email me privately if you wish.

The correction of geometry on Steinway stacks is all but easy (but necessary often) I like to modify the old stack, just because of the difference in flange size, to avoid too much shimming (the holes have to be enlarged) but actually I would like to use directly the parts at the original dimensions.

I have seen a set mounted on an old NY Steinway that sounded well adapted, geometry wise. I thought of Tokiwa but cannot be certain. Nice shanks, good cold pressed heads, I suppose it is sort of a standard on the old NY models, but liked to know where are the parts from (I can send pics)

Too bad someone rubbed the knuckles with graphite while the piano could be regulated correctly without that, if only one accept to have 6 leads in the basses )

The action ratio seem to be fantasist on the old models, changing from one to the next....

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HI Jim ! I did not notice so high uneveness on the stacks I soldered, (also because the rails are cracked in that case generally, I cannot account the stack for an "original "geometry)

Your experimentation is interesting, for sure there is some amount of pressure between the foot and the wedge, and it may move the centers (I did not make such experiments, but I will)

I sold the stack on a flat bench, but I measure /verify the centers. As I use a "copy" jig I have find some nice uneveness in rails, as a warping in the mediums, that was only due to the soldering in my opinion.

Witch order for the soldering, would be the most secure, in your opinion ? (to avoid the warpage due to the soldering heat ?

I am unsure if it is better to begin in the center, or at the extremes. (my gig allows 3 points secured)

I teach a class called "Understanding the S&S Tubular Rail Frame"...I will be presenting it at MARC this year. Having examined these frames from the perspective of dead-nuts production accuracy across the frame, and having developed the procedures and equipment to actually accurately measure and target this I can safely say that the level of center inconsistency, at least in vintage and stacks well through the 1980's explains much about the inconsistency techs have complained about in S&S actions for years.

When rebuilding a frame in your shop, you will find inconsistency in the newly soldered frames if the old rails have been indexed to the old. This is because the old rails were inconsistent due to:

-positioning inaccuracies in the original factory fabrication...very common-old split rails often untwist as the split, moving the flange centers with the twist...sometimes increasing spread, at points in the rail, by 2-4mm-solder faiure...though I don't find this to be a dimensional issue as much as a flapping- around-in-play issue.

also keep in mind:

-new rails all have twist. They are almost never without twist...from 1 deg to 3 deg, which depending on the flange can make a significant difference in flange center locations, unless the soldering jig is designed to correct for this inaccuracy.-new rails are bowed. Even if you take the bow out before boring, after they are bored, the rails will take on a new bow as the boring changes the stress pattern in the rail/dowel.

Perhaps some twist is introduced in the soldering process, but with my setup, I have not noticed this changing spread more than .33mm, and usually only when soldering the hammer rail. Its more a matter of having a setup jig capable of correcting for the twist and bow the new rails all exhibit.

Originally Posted By: Kamin

The correction of geometry on Steinway stacks is all but easy (but necessary often) I like to modify the old stack, just because of the difference in flange size, to avoid too much shimming (the holes have to be enlarged) but actually I would like to use directly the parts at the original dimensions.

I have seen a set mounted on an old NY Steinway that sounded well adapted, geometry wise. I thought of Tokiwa but cannot be certain. Nice shanks, good cold pressed heads, I suppose it is sort of a standard on the old NY models, but liked to know where are the parts from (I can send pics)

An understatement. This is an incredibly challenging frame to control in fabrication, especially in a factory production setting.

You mention different aftermarket parts...Each manufacturer's "S&S" flanges have different center location in relation to where the flange sits on the rail. In a rebuild, if you choose to use the existing frame unaltered, you can sometimes use this difference between aftermarket parts to your advantage, as Tokiwa whip flange will decrease existing spread by almost 2mm depending on the setup, and Renner and WNG will increase the spread a bit as well. By mixing and matching, as long as you knew what geometry to shoot for, you could get pretty close, assuming the existing rails are not too wildly inconsistnet to begin with.

I don't mix and match, but I have the equipment to put the rails/centers where I want them with the chosen parts.

decreasing the spread (even 1 mm) ? I though that the Tokiwa parts where more in the good dimensions (at last for the shanks)

I have some new rail I will analyses with what you wrote in mind.

The bowed rails I have seen where misplaced and the bow was apparently due to the thin plank in the mediums, to sold the rail straight, the hole should be enlarged (due to improper positioning somewhere.

Too time consuming probably.

The angles, they are very difficult to manage precisely. I believe we may find similar angles at the wedges and for the rails

I for sure see the challenge it is to have those stacks normalized, (just the feet bending is something surprising !) but still they have many advantages.

I suggest that there are also inconsistencies. in balance rail position, the spread is sensitive if we are in the 111 mm region, but as soon as we are in more common dimensions there is some margin.

Steinways action make me work the action analysis thru tactile feedback, as measuring and finding the mistake source is rarely easy. I am now sensitive to keyboard acceleration (magic line position) and to the quality of the letof/drop rub. Recognizing those as sensations when moving the notes very slowly is often a big help (but mistakes and confusions happens indeed !).

I plan to add a 4th support to my jig , the 3 points allow to align but that could be more precise (that said I have seen new rails soldered with a very basic setup, shims to lock the tubes and a rough control in 5-6 places, in the end may be not worse than originally...).

Edited by Kamin (11/12/1208:40 AM)

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Very interesting reading Ed, Jim and Kamin, thanks for the replies!I took some measurements today.

With the action sitting flat on the keyframe (plus 4mm shim front side and 2mm shim back side in the treble to fill the gap).

HCP height is consistent at 144mm.Repetition CP is 80mm in the bass and middle, and 79mm in the treble and top treble.

without the shims, the treble end HCP would be pulled down an additional 4mm and RCP down 2mm...

String height is 190/189mm tapering to 187mm in the top treble.Hammer bore is 45mm.

Another thing i noticed was that the keyframe front rail is 2.5mm thicker in the bass than in the treble.This is another thing i don't think i've come across before, what would be the reason for this?-I thought for a bit that it might be to bed the keyframe or something due to the 'twist' in the action, but that would make it worse, as it would want to be thicker in the treble wouldn't it?

The bedding is best with the shims too..

This steinway is very quirky!

I emailed Kent back today with the serial number that he requested, so i haven't heard his suggestions yet..Should be interesting.